Vendor Update: go-gitlab v0.22.1 -> v0.31.0 (#11136)

* vendor update: go-gitlab to v0.31.0

* migrate client init to v0.31.0

* refactor

15 files changed, 1736 insertions, 0 deletions

diff --git a/vendor/github.com/hashicorp/go-cleanhttp/LICENSE b/vendor/github.com/hashicorp/go-cleanhttp/LICENSE
new file mode 100644
index 0000000000..e87a115e46
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-cleanhttp/LICENSE
@@ -0,0 +1,363 @@
+Mozilla Public License, version 2.0
+
+1. Definitions
+
+1.1. "Contributor"
+
+     means each individual or legal entity that creates, contributes to the
+     creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+
+     means the combination of the Contributions of others (if any) used by a
+     Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+
+     means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+
+     means Source Code Form to which the initial Contributor has attached the
+     notice in Exhibit A, the Executable Form of such Source Code Form, and
+     Modifications of such Source Code Form, in each case including portions
+     thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+     means
+
+     a. that the initial Contributor has attached the notice described in
+        Exhibit B to the Covered Software; or
+
+     b. that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the terms of
+        a Secondary License.
+
+1.6. "Executable Form"
+
+     means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+
+     means a work that combines Covered Software with other material, in a
+     separate file or files, that is not Covered Software.
+
+1.8. "License"
+
+     means this document.
+
+1.9. "Licensable"
+
+     means having the right to grant, to the maximum extent possible, whether
+     at the time of the initial grant or subsequently, any and all of the
+     rights conveyed by this License.
+
+1.10. "Modifications"
+
+     means any of the following:
+
+     a. any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered Software; or
+
+     b. any new file in Source Code Form that contains any Covered Software.
+
+1.11. "Patent Claims" of a Contributor
+
+      means any patent claim(s), including without limitation, method,
+      process, and apparatus claims, in any patent Licensable by such
+      Contributor that would be infringed, but for the grant of the License,
+      by the making, using, selling, offering for sale, having made, import,
+      or transfer of either its Contributions or its Contributor Version.
+
+1.12. "Secondary License"
+
+      means either the GNU General Public License, Version 2.0, the GNU Lesser
+      General Public License, Version 2.1, the GNU Affero General Public
+      License, Version 3.0, or any later versions of those licenses.
+
+1.13. "Source Code Form"
+
+      means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+
+      means an individual or a legal entity exercising rights under this
+      License. For legal entities, "You" includes any entity that controls, is
+      controlled by, or is under common control with You. For purposes of this
+      definition, "control" means (a) the power, direct or indirect, to cause
+      the direction or management of such entity, whether by contract or
+      otherwise, or (b) ownership of more than fifty percent (50%) of the
+      outstanding shares or beneficial ownership of such entity.
+
+
+2. License Grants and Conditions
+
+2.1. Grants
+
+     Each Contributor hereby grants You a world-wide, royalty-free,
+     non-exclusive license:
+
+     a. under intellectual property rights (other than patent or trademark)
+        Licensable by such Contributor to use, reproduce, make available,
+        modify, display, perform, distribute, and otherwise exploit its
+        Contributions, either on an unmodified basis, with Modifications, or
+        as part of a Larger Work; and
+
+     b. under Patent Claims of such Contributor to make, use, sell, offer for
+        sale, have made, import, and otherwise transfer either its
+        Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+     The licenses granted in Section 2.1 with respect to any Contribution
+     become effective for each Contribution on the date the Contributor first
+     distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+     The licenses granted in this Section 2 are the only rights granted under
+     this License. No additional rights or licenses will be implied from the
+     distribution or licensing of Covered Software under this License.
+     Notwithstanding Section 2.1(b) above, no patent license is granted by a
+     Contributor:
+
+     a. for any code that a Contributor has removed from Covered Software; or
+
+     b. for infringements caused by: (i) Your and any other third party's
+        modifications of Covered Software, or (ii) the combination of its
+        Contributions with other software (except as part of its Contributor
+        Version); or
+
+     c. under Patent Claims infringed by Covered Software in the absence of
+        its Contributions.
+
+     This License does not grant any rights in the trademarks, service marks,
+     or logos of any Contributor (except as may be necessary to comply with
+     the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+     No Contributor makes additional grants as a result of Your choice to
+     distribute the Covered Software under a subsequent version of this
+     License (see Section 10.2) or under the terms of a Secondary License (if
+     permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+     Each Contributor represents that the Contributor believes its
+     Contributions are its original creation(s) or it has sufficient rights to
+     grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+     This License is not intended to limit any rights You have under
+     applicable copyright doctrines of fair use, fair dealing, or other
+     equivalents.
+
+2.7. Conditions
+
+     Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+     Section 2.1.
+
+
+3. Responsibilities
+
+3.1. Distribution of Source Form
+
+     All distribution of Covered Software in Source Code Form, including any
+     Modifications that You create or to which You contribute, must be under
+     the terms of this License. You must inform recipients that the Source
+     Code Form of the Covered Software is governed by the terms of this
+     License, and how they can obtain a copy of this License. You may not
+     attempt to alter or restrict the recipients' rights in the Source Code
+     Form.
+
+3.2. Distribution of Executable Form
+
+     If You distribute Covered Software in Executable Form then:
+
+     a. such Covered Software must also be made available in Source Code Form,
+        as described in Section 3.1, and You must inform recipients of the
+        Executable Form how they can obtain a copy of such Source Code Form by
+        reasonable means in a timely manner, at a charge no more than the cost
+        of distribution to the recipient; and
+
+     b. You may distribute such Executable Form under the terms of this
+        License, or sublicense it under different terms, provided that the
+        license for the Executable Form does not attempt to limit or alter the
+        recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+     You may create and distribute a Larger Work under terms of Your choice,
+     provided that You also comply with the requirements of this License for
+     the Covered Software. If the Larger Work is a combination of Covered
+     Software with a work governed by one or more Secondary Licenses, and the
+     Covered Software is not Incompatible With Secondary Licenses, this
+     License permits You to additionally distribute such Covered Software
+     under the terms of such Secondary License(s), so that the recipient of
+     the Larger Work may, at their option, further distribute the Covered
+     Software under the terms of either this License or such Secondary
+     License(s).
+
+3.4. Notices
+
+     You may not remove or alter the substance of any license notices
+     (including copyright notices, patent notices, disclaimers of warranty, or
+     limitations of liability) contained within the Source Code Form of the
+     Covered Software, except that You may alter any license notices to the
+     extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+     You may choose to offer, and to charge a fee for, warranty, support,
+     indemnity or liability obligations to one or more recipients of Covered
+     Software. However, You may do so only on Your own behalf, and not on
+     behalf of any Contributor. You must make it absolutely clear that any
+     such warranty, support, indemnity, or liability obligation is offered by
+     You alone, and You hereby agree to indemnify every Contributor for any
+     liability incurred by such Contributor as a result of warranty, support,
+     indemnity or liability terms You offer. You may include additional
+     disclaimers of warranty and limitations of liability specific to any
+     jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+
+   If it is impossible for You to comply with any of the terms of this License
+   with respect to some or all of the Covered Software due to statute,
+   judicial order, or regulation then You must: (a) comply with the terms of
+   this License to the maximum extent possible; and (b) describe the
+   limitations and the code they affect. Such description must be placed in a
+   text file included with all distributions of the Covered Software under
+   this License. Except to the extent prohibited by statute or regulation,
+   such description must be sufficiently detailed for a recipient of ordinary
+   skill to be able to understand it.
+
+5. Termination
+
+5.1. The rights granted under this License will terminate automatically if You
+     fail to comply with any of its terms. However, if You become compliant,
+     then the rights granted under this License from a particular Contributor
+     are reinstated (a) provisionally, unless and until such Contributor
+     explicitly and finally terminates Your grants, and (b) on an ongoing
+     basis, if such Contributor fails to notify You of the non-compliance by
+     some reasonable means prior to 60 days after You have come back into
+     compliance. Moreover, Your grants from a particular Contributor are
+     reinstated on an ongoing basis if such Contributor notifies You of the
+     non-compliance by some reasonable means, this is the first time You have
+     received notice of non-compliance with this License from such
+     Contributor, and You become compliant prior to 30 days after Your receipt
+     of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+     infringement claim (excluding declaratory judgment actions,
+     counter-claims, and cross-claims) alleging that a Contributor Version
+     directly or indirectly infringes any patent, then the rights granted to
+     You by any and all Contributors for the Covered Software under Section
+     2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
+     license agreements (excluding distributors and resellers) which have been
+     validly granted by You or Your distributors under this License prior to
+     termination shall survive termination.
+
+6. Disclaimer of Warranty
+
+   Covered Software is provided under this License on an "as is" basis,
+   without warranty of any kind, either expressed, implied, or statutory,
+   including, without limitation, warranties that the Covered Software is free
+   of defects, merchantable, fit for a particular purpose or non-infringing.
+   The entire risk as to the quality and performance of the Covered Software
+   is with You. Should any Covered Software prove defective in any respect,
+   You (not any Contributor) assume the cost of any necessary servicing,
+   repair, or correction. This disclaimer of warranty constitutes an essential
+   part of this License. No use of  any Covered Software is authorized under
+   this License except under this disclaimer.
+
+7. Limitation of Liability
+
+   Under no circumstances and under no legal theory, whether tort (including
+   negligence), contract, or otherwise, shall any Contributor, or anyone who
+   distributes Covered Software as permitted above, be liable to You for any
+   direct, indirect, special, incidental, or consequential damages of any
+   character including, without limitation, damages for lost profits, loss of
+   goodwill, work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses, even if such party shall have been
+   informed of the possibility of such damages. This limitation of liability
+   shall not apply to liability for death or personal injury resulting from
+   such party's negligence to the extent applicable law prohibits such
+   limitation. Some jurisdictions do not allow the exclusion or limitation of
+   incidental or consequential damages, so this exclusion and limitation may
+   not apply to You.
+
+8. Litigation
+
+   Any litigation relating to this License may be brought only in the courts
+   of a jurisdiction where the defendant maintains its principal place of
+   business and such litigation shall be governed by laws of that
+   jurisdiction, without reference to its conflict-of-law provisions. Nothing
+   in this Section shall prevent a party's ability to bring cross-claims or
+   counter-claims.
+
+9. Miscellaneous
+
+   This License represents the complete agreement concerning the subject
+   matter hereof. If any provision of this License is held to be
+   unenforceable, such provision shall be reformed only to the extent
+   necessary to make it enforceable. Any law or regulation which provides that
+   the language of a contract shall be construed against the drafter shall not
+   be used to construe this License against a Contributor.
+
+
+10. Versions of the License
+
+10.1. New Versions
+
+      Mozilla Foundation is the license steward. Except as provided in Section
+      10.3, no one other than the license steward has the right to modify or
+      publish new versions of this License. Each version will be given a
+      distinguishing version number.
+
+10.2. Effect of New Versions
+
+      You may distribute the Covered Software under the terms of the version
+      of the License under which You originally received the Covered Software,
+      or under the terms of any subsequent version published by the license
+      steward.
+
+10.3. Modified Versions
+
+      If you create software not governed by this License, and you want to
+      create a new license for such software, you may create and use a
+      modified version of this License if you rename the license and remove
+      any references to the name of the license steward (except to note that
+      such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+      Licenses If You choose to distribute Source Code Form that is
+      Incompatible With Secondary Licenses under the terms of this version of
+      the License, the notice described in Exhibit B of this License must be
+      attached.
+
+Exhibit A - Source Code Form License Notice
+
+      This Source Code Form is subject to the
+      terms of the Mozilla Public License, v.
+      2.0. If a copy of the MPL was not
+      distributed with this file, You can
+      obtain one at
+      http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular file,
+then You may include the notice in a location (such as a LICENSE file in a
+relevant directory) where a recipient would be likely to look for such a
+notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+
+      This Source Code Form is "Incompatible
+      With Secondary Licenses", as defined by
+      the Mozilla Public License, v. 2.0.
+
diff --git a/vendor/github.com/hashicorp/go-cleanhttp/README.md b/vendor/github.com/hashicorp/go-cleanhttp/README.md
new file mode 100644
index 0000000000..036e5313fc
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-cleanhttp/README.md
@@ -0,0 +1,30 @@
+# cleanhttp
+
+Functions for accessing "clean" Go http.Client values
+
+-------------
+
+The Go standard library contains a default `http.Client` called
+`http.DefaultClient`. It is a common idiom in Go code to start with
+`http.DefaultClient` and tweak it as necessary, and in fact, this is
+encouraged; from the `http` package documentation:
+
+> The Client's Transport typically has internal state (cached TCP connections),
+so Clients should be reused instead of created as needed. Clients are safe for
+concurrent use by multiple goroutines.
+
+Unfortunately, this is a shared value, and it is not uncommon for libraries to
+assume that they are free to modify it at will. With enough dependencies, it
+can be very easy to encounter strange problems and race conditions due to
+manipulation of this shared value across libraries and goroutines (clients are
+safe for concurrent use, but writing values to the client struct itself is not
+protected).
+
+Making things worse is the fact that a bare `http.Client` will use a default
+`http.Transport` called `http.DefaultTransport`, which is another global value
+that behaves the same way. So it is not simply enough to replace
+`http.DefaultClient` with `&http.Client{}`.
+
+This repository provides some simple functions to get a "clean" `http.Client`
+-- one that uses the same default values as the Go standard library, but
+returns a client that does not share any state with other clients.
diff --git a/vendor/github.com/hashicorp/go-cleanhttp/cleanhttp.go b/vendor/github.com/hashicorp/go-cleanhttp/cleanhttp.go
new file mode 100644
index 0000000000..8d306bf513
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-cleanhttp/cleanhttp.go
@@ -0,0 +1,57 @@
+package cleanhttp
+
+import (
+	"net"
+	"net/http"
+	"runtime"
+	"time"
+)
+
+// DefaultTransport returns a new http.Transport with similar default values to
+// http.DefaultTransport, but with idle connections and keepalives disabled.
+func DefaultTransport() *http.Transport {
+	transport := DefaultPooledTransport()
+	transport.DisableKeepAlives = true
+	transport.MaxIdleConnsPerHost = -1
+	return transport
+}
+
+// DefaultPooledTransport returns a new http.Transport with similar default
+// values to http.DefaultTransport. Do not use this for transient transports as
+// it can leak file descriptors over time. Only use this for transports that
+// will be re-used for the same host(s).
+func DefaultPooledTransport() *http.Transport {
+	transport := &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+			DualStack: true,
+		}).DialContext,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+		MaxIdleConnsPerHost:   runtime.GOMAXPROCS(0) + 1,
+	}
+	return transport
+}
+
+// DefaultClient returns a new http.Client with similar default values to
+// http.Client, but with a non-shared Transport, idle connections disabled, and
+// keepalives disabled.
+func DefaultClient() *http.Client {
+	return &http.Client{
+		Transport: DefaultTransport(),
+	}
+}
+
+// DefaultPooledClient returns a new http.Client with similar default values to
+// http.Client, but with a shared Transport. Do not use this function for
+// transient clients as it can leak file descriptors over time. Only use this
+// for clients that will be re-used for the same host(s).
+func DefaultPooledClient() *http.Client {
+	return &http.Client{
+		Transport: DefaultPooledTransport(),
+	}
+}
diff --git a/vendor/github.com/hashicorp/go-cleanhttp/doc.go b/vendor/github.com/hashicorp/go-cleanhttp/doc.go
new file mode 100644
index 0000000000..05841092a7
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-cleanhttp/doc.go
@@ -0,0 +1,20 @@
+// Package cleanhttp offers convenience utilities for acquiring "clean"
+// http.Transport and http.Client structs.
+//
+// Values set on http.DefaultClient and http.DefaultTransport affect all
+// callers. This can have detrimental effects, esepcially in TLS contexts,
+// where client or root certificates set to talk to multiple endpoints can end
+// up displacing each other, leading to hard-to-debug issues. This package
+// provides non-shared http.Client and http.Transport structs to ensure that
+// the configuration will not be overwritten by other parts of the application
+// or dependencies.
+//
+// The DefaultClient and DefaultTransport functions disable idle connections
+// and keepalives. Without ensuring that idle connections are closed before
+// garbage collection, short-term clients/transports can leak file descriptors,
+// eventually leading to "too many open files" errors. If you will be
+// connecting to the same hosts repeatedly from the same client, you can use
+// DefaultPooledClient to receive a client that has connection pooling
+// semantics similar to http.DefaultClient.
+//
+package cleanhttp
diff --git a/vendor/github.com/hashicorp/go-cleanhttp/go.mod b/vendor/github.com/hashicorp/go-cleanhttp/go.mod
new file mode 100644
index 0000000000..310f07569f
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-cleanhttp/go.mod
@@ -0,0 +1 @@
+module github.com/hashicorp/go-cleanhttp
diff --git a/vendor/github.com/hashicorp/go-cleanhttp/handlers.go b/vendor/github.com/hashicorp/go-cleanhttp/handlers.go
new file mode 100644
index 0000000000..3c845dc0dc
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-cleanhttp/handlers.go
@@ -0,0 +1,48 @@
+package cleanhttp
+
+import (
+	"net/http"
+	"strings"
+	"unicode"
+)
+
+// HandlerInput provides input options to cleanhttp's handlers
+type HandlerInput struct {
+	ErrStatus int
+}
+
+// PrintablePathCheckHandler is a middleware that ensures the request path
+// contains only printable runes.
+func PrintablePathCheckHandler(next http.Handler, input *HandlerInput) http.Handler {
+	// Nil-check on input to make it optional
+	if input == nil {
+		input = &HandlerInput{
+			ErrStatus: http.StatusBadRequest,
+		}
+	}
+
+	// Default to http.StatusBadRequest on error
+	if input.ErrStatus == 0 {
+		input.ErrStatus = http.StatusBadRequest
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r != nil {
+			// Check URL path for non-printable characters
+			idx := strings.IndexFunc(r.URL.Path, func(c rune) bool {
+				return !unicode.IsPrint(c)
+			})
+
+			if idx != -1 {
+				w.WriteHeader(input.ErrStatus)
+				return
+			}
+
+			if next != nil {
+				next.ServeHTTP(w, r)
+			}
+		}
+
+		return
+	})
+}
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/.gitignore b/vendor/github.com/hashicorp/go-retryablehttp/.gitignore
new file mode 100644
index 0000000000..4e309e0b32
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-retryablehttp/.gitignore
@@ -0,0 +1,4 @@
+.idea/
+*.iml
+*.test
+.vscode/
\ No newline at end of file
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/.travis.yml b/vendor/github.com/hashicorp/go-retryablehttp/.travis.yml
new file mode 100644
index 0000000000..c4fb6d6c8b
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-retryablehttp/.travis.yml
@@ -0,0 +1,12 @@
+sudo: false
+
+language: go
+
+go:
+  - 1.12.4
+
+branches:
+  only:
+    - master
+
+script: make updatedeps test
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/LICENSE b/vendor/github.com/hashicorp/go-retryablehttp/LICENSE
new file mode 100644
index 0000000000..e87a115e46
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-retryablehttp/LICENSE
@@ -0,0 +1,363 @@
+Mozilla Public License, version 2.0
+
+1. Definitions
+
+1.1. "Contributor"
+
+     means each individual or legal entity that creates, contributes to the
+     creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+
+     means the combination of the Contributions of others (if any) used by a
+     Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+
+     means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+
+     means Source Code Form to which the initial Contributor has attached the
+     notice in Exhibit A, the Executable Form of such Source Code Form, and
+     Modifications of such Source Code Form, in each case including portions
+     thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+     means
+
+     a. that the initial Contributor has attached the notice described in
+        Exhibit B to the Covered Software; or
+
+     b. that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the terms of
+        a Secondary License.
+
+1.6. "Executable Form"
+
+     means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+
+     means a work that combines Covered Software with other material, in a
+     separate file or files, that is not Covered Software.
+
+1.8. "License"
+
+     means this document.
+
+1.9. "Licensable"
+
+     means having the right to grant, to the maximum extent possible, whether
+     at the time of the initial grant or subsequently, any and all of the
+     rights conveyed by this License.
+
+1.10. "Modifications"
+
+     means any of the following:
+
+     a. any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered Software; or
+
+     b. any new file in Source Code Form that contains any Covered Software.
+
+1.11. "Patent Claims" of a Contributor
+
+      means any patent claim(s), including without limitation, method,
+      process, and apparatus claims, in any patent Licensable by such
+      Contributor that would be infringed, but for the grant of the License,
+      by the making, using, selling, offering for sale, having made, import,
+      or transfer of either its Contributions or its Contributor Version.
+
+1.12. "Secondary License"
+
+      means either the GNU General Public License, Version 2.0, the GNU Lesser
+      General Public License, Version 2.1, the GNU Affero General Public
+      License, Version 3.0, or any later versions of those licenses.
+
+1.13. "Source Code Form"
+
+      means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+
+      means an individual or a legal entity exercising rights under this
+      License. For legal entities, "You" includes any entity that controls, is
+      controlled by, or is under common control with You. For purposes of this
+      definition, "control" means (a) the power, direct or indirect, to cause
+      the direction or management of such entity, whether by contract or
+      otherwise, or (b) ownership of more than fifty percent (50%) of the
+      outstanding shares or beneficial ownership of such entity.
+
+
+2. License Grants and Conditions
+
+2.1. Grants
+
+     Each Contributor hereby grants You a world-wide, royalty-free,
+     non-exclusive license:
+
+     a. under intellectual property rights (other than patent or trademark)
+        Licensable by such Contributor to use, reproduce, make available,
+        modify, display, perform, distribute, and otherwise exploit its
+        Contributions, either on an unmodified basis, with Modifications, or
+        as part of a Larger Work; and
+
+     b. under Patent Claims of such Contributor to make, use, sell, offer for
+        sale, have made, import, and otherwise transfer either its
+        Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+     The licenses granted in Section 2.1 with respect to any Contribution
+     become effective for each Contribution on the date the Contributor first
+     distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+     The licenses granted in this Section 2 are the only rights granted under
+     this License. No additional rights or licenses will be implied from the
+     distribution or licensing of Covered Software under this License.
+     Notwithstanding Section 2.1(b) above, no patent license is granted by a
+     Contributor:
+
+     a. for any code that a Contributor has removed from Covered Software; or
+
+     b. for infringements caused by: (i) Your and any other third party's
+        modifications of Covered Software, or (ii) the combination of its
+        Contributions with other software (except as part of its Contributor
+        Version); or
+
+     c. under Patent Claims infringed by Covered Software in the absence of
+        its Contributions.
+
+     This License does not grant any rights in the trademarks, service marks,
+     or logos of any Contributor (except as may be necessary to comply with
+     the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+     No Contributor makes additional grants as a result of Your choice to
+     distribute the Covered Software under a subsequent version of this
+     License (see Section 10.2) or under the terms of a Secondary License (if
+     permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+     Each Contributor represents that the Contributor believes its
+     Contributions are its original creation(s) or it has sufficient rights to
+     grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+     This License is not intended to limit any rights You have under
+     applicable copyright doctrines of fair use, fair dealing, or other
+     equivalents.
+
+2.7. Conditions
+
+     Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+     Section 2.1.
+
+
+3. Responsibilities
+
+3.1. Distribution of Source Form
+
+     All distribution of Covered Software in Source Code Form, including any
+     Modifications that You create or to which You contribute, must be under
+     the terms of this License. You must inform recipients that the Source
+     Code Form of the Covered Software is governed by the terms of this
+     License, and how they can obtain a copy of this License. You may not
+     attempt to alter or restrict the recipients' rights in the Source Code
+     Form.
+
+3.2. Distribution of Executable Form
+
+     If You distribute Covered Software in Executable Form then:
+
+     a. such Covered Software must also be made available in Source Code Form,
+        as described in Section 3.1, and You must inform recipients of the
+        Executable Form how they can obtain a copy of such Source Code Form by
+        reasonable means in a timely manner, at a charge no more than the cost
+        of distribution to the recipient; and
+
+     b. You may distribute such Executable Form under the terms of this
+        License, or sublicense it under different terms, provided that the
+        license for the Executable Form does not attempt to limit or alter the
+        recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+     You may create and distribute a Larger Work under terms of Your choice,
+     provided that You also comply with the requirements of this License for
+     the Covered Software. If the Larger Work is a combination of Covered
+     Software with a work governed by one or more Secondary Licenses, and the
+     Covered Software is not Incompatible With Secondary Licenses, this
+     License permits You to additionally distribute such Covered Software
+     under the terms of such Secondary License(s), so that the recipient of
+     the Larger Work may, at their option, further distribute the Covered
+     Software under the terms of either this License or such Secondary
+     License(s).
+
+3.4. Notices
+
+     You may not remove or alter the substance of any license notices
+     (including copyright notices, patent notices, disclaimers of warranty, or
+     limitations of liability) contained within the Source Code Form of the
+     Covered Software, except that You may alter any license notices to the
+     extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+     You may choose to offer, and to charge a fee for, warranty, support,
+     indemnity or liability obligations to one or more recipients of Covered
+     Software. However, You may do so only on Your own behalf, and not on
+     behalf of any Contributor. You must make it absolutely clear that any
+     such warranty, support, indemnity, or liability obligation is offered by
+     You alone, and You hereby agree to indemnify every Contributor for any
+     liability incurred by such Contributor as a result of warranty, support,
+     indemnity or liability terms You offer. You may include additional
+     disclaimers of warranty and limitations of liability specific to any
+     jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+
+   If it is impossible for You to comply with any of the terms of this License
+   with respect to some or all of the Covered Software due to statute,
+   judicial order, or regulation then You must: (a) comply with the terms of
+   this License to the maximum extent possible; and (b) describe the
+   limitations and the code they affect. Such description must be placed in a
+   text file included with all distributions of the Covered Software under
+   this License. Except to the extent prohibited by statute or regulation,
+   such description must be sufficiently detailed for a recipient of ordinary
+   skill to be able to understand it.
+
+5. Termination
+
+5.1. The rights granted under this License will terminate automatically if You
+     fail to comply with any of its terms. However, if You become compliant,
+     then the rights granted under this License from a particular Contributor
+     are reinstated (a) provisionally, unless and until such Contributor
+     explicitly and finally terminates Your grants, and (b) on an ongoing
+     basis, if such Contributor fails to notify You of the non-compliance by
+     some reasonable means prior to 60 days after You have come back into
+     compliance. Moreover, Your grants from a particular Contributor are
+     reinstated on an ongoing basis if such Contributor notifies You of the
+     non-compliance by some reasonable means, this is the first time You have
+     received notice of non-compliance with this License from such
+     Contributor, and You become compliant prior to 30 days after Your receipt
+     of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+     infringement claim (excluding declaratory judgment actions,
+     counter-claims, and cross-claims) alleging that a Contributor Version
+     directly or indirectly infringes any patent, then the rights granted to
+     You by any and all Contributors for the Covered Software under Section
+     2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
+     license agreements (excluding distributors and resellers) which have been
+     validly granted by You or Your distributors under this License prior to
+     termination shall survive termination.
+
+6. Disclaimer of Warranty
+
+   Covered Software is provided under this License on an "as is" basis,
+   without warranty of any kind, either expressed, implied, or statutory,
+   including, without limitation, warranties that the Covered Software is free
+   of defects, merchantable, fit for a particular purpose or non-infringing.
+   The entire risk as to the quality and performance of the Covered Software
+   is with You. Should any Covered Software prove defective in any respect,
+   You (not any Contributor) assume the cost of any necessary servicing,
+   repair, or correction. This disclaimer of warranty constitutes an essential
+   part of this License. No use of  any Covered Software is authorized under
+   this License except under this disclaimer.
+
+7. Limitation of Liability
+
+   Under no circumstances and under no legal theory, whether tort (including
+   negligence), contract, or otherwise, shall any Contributor, or anyone who
+   distributes Covered Software as permitted above, be liable to You for any
+   direct, indirect, special, incidental, or consequential damages of any
+   character including, without limitation, damages for lost profits, loss of
+   goodwill, work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses, even if such party shall have been
+   informed of the possibility of such damages. This limitation of liability
+   shall not apply to liability for death or personal injury resulting from
+   such party's negligence to the extent applicable law prohibits such
+   limitation. Some jurisdictions do not allow the exclusion or limitation of
+   incidental or consequential damages, so this exclusion and limitation may
+   not apply to You.
+
+8. Litigation
+
+   Any litigation relating to this License may be brought only in the courts
+   of a jurisdiction where the defendant maintains its principal place of
+   business and such litigation shall be governed by laws of that
+   jurisdiction, without reference to its conflict-of-law provisions. Nothing
+   in this Section shall prevent a party's ability to bring cross-claims or
+   counter-claims.
+
+9. Miscellaneous
+
+   This License represents the complete agreement concerning the subject
+   matter hereof. If any provision of this License is held to be
+   unenforceable, such provision shall be reformed only to the extent
+   necessary to make it enforceable. Any law or regulation which provides that
+   the language of a contract shall be construed against the drafter shall not
+   be used to construe this License against a Contributor.
+
+
+10. Versions of the License
+
+10.1. New Versions
+
+      Mozilla Foundation is the license steward. Except as provided in Section
+      10.3, no one other than the license steward has the right to modify or
+      publish new versions of this License. Each version will be given a
+      distinguishing version number.
+
+10.2. Effect of New Versions
+
+      You may distribute the Covered Software under the terms of the version
+      of the License under which You originally received the Covered Software,
+      or under the terms of any subsequent version published by the license
+      steward.
+
+10.3. Modified Versions
+
+      If you create software not governed by this License, and you want to
+      create a new license for such software, you may create and use a
+      modified version of this License if you rename the license and remove
+      any references to the name of the license steward (except to note that
+      such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+      Licenses If You choose to distribute Source Code Form that is
+      Incompatible With Secondary Licenses under the terms of this version of
+      the License, the notice described in Exhibit B of this License must be
+      attached.
+
+Exhibit A - Source Code Form License Notice
+
+      This Source Code Form is subject to the
+      terms of the Mozilla Public License, v.
+      2.0. If a copy of the MPL was not
+      distributed with this file, You can
+      obtain one at
+      http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular file,
+then You may include the notice in a location (such as a LICENSE file in a
+relevant directory) where a recipient would be likely to look for such a
+notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+
+      This Source Code Form is "Incompatible
+      With Secondary Licenses", as defined by
+      the Mozilla Public License, v. 2.0.
+
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/Makefile b/vendor/github.com/hashicorp/go-retryablehttp/Makefile
new file mode 100644
index 0000000000..da17640e64
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-retryablehttp/Makefile
@@ -0,0 +1,11 @@
+default: test
+
+test:
+	go vet ./...
+	go test -race ./...
+
+updatedeps:
+	go get -f -t -u ./...
+	go get -f -u ./...
+
+.PHONY: default test updatedeps
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/README.md b/vendor/github.com/hashicorp/go-retryablehttp/README.md
new file mode 100644
index 0000000000..30357c7566
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-retryablehttp/README.md
@@ -0,0 +1,61 @@
+go-retryablehttp
+================
+
+[![Build Status](http://img.shields.io/travis/hashicorp/go-retryablehttp.svg?style=flat-square)][travis]
+[![Go Documentation](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)][godocs]
+
+[travis]: http://travis-ci.org/hashicorp/go-retryablehttp
+[godocs]: http://godoc.org/github.com/hashicorp/go-retryablehttp
+
+The `retryablehttp` package provides a familiar HTTP client interface with
+automatic retries and exponential backoff. It is a thin wrapper over the
+standard `net/http` client library and exposes nearly the same public API. This
+makes `retryablehttp` very easy to drop into existing programs.
+
+`retryablehttp` performs automatic retries under certain conditions. Mainly, if
+an error is returned by the client (connection errors, etc.), or if a 500-range
+response code is received (except 501), then a retry is invoked after a wait
+period.  Otherwise, the response is returned and left to the caller to
+interpret.
+
+The main difference from `net/http` is that requests which take a request body
+(POST/PUT et. al) can have the body provided in a number of ways (some more or
+less efficient) that allow "rewinding" the request body if the initial request
+fails so that the full request can be attempted again. See the
+[godoc](http://godoc.org/github.com/hashicorp/go-retryablehttp) for more
+details.
+
+Version 0.6.0 and before are compatible with Go prior to 1.12. From 0.6.1 onward, Go 1.12+ is required.
+
+Example Use
+===========
+
+Using this library should look almost identical to what you would do with
+`net/http`. The most simple example of a GET request is shown below:
+
+```go
+resp, err := retryablehttp.Get("/foo")
+if err != nil {
+    panic(err)
+}
+```
+
+The returned response object is an `*http.Response`, the same thing you would
+usually get from `net/http`. Had the request failed one or more times, the above
+call would block and retry with exponential backoff.
+
+## Getting a stdlib `*http.Client` with retries
+
+It's possible to convert a `*retryablehttp.Client` directly to a `*http.Client`.
+This makes use of retryablehttp broadly applicable with minimal effort. Simply
+configure a `*retryablehttp.Client` as you wish, and then call `StandardClient()`:
+
+```go
+retryClient := retryablehttp.NewClient()
+retryClient.RetryMax = 10
+
+standardClient := retryClient.StandardClient() // *http.Client
+```
+
+For more usage and examples see the
+[godoc](http://godoc.org/github.com/hashicorp/go-retryablehttp).
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/client.go b/vendor/github.com/hashicorp/go-retryablehttp/client.go
new file mode 100644
index 0000000000..f1ccd3df35
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-retryablehttp/client.go
@@ -0,0 +1,705 @@
+// Package retryablehttp provides a familiar HTTP client interface with
+// automatic retries and exponential backoff. It is a thin wrapper over the
+// standard net/http client library and exposes nearly the same public API.
+// This makes retryablehttp very easy to drop into existing programs.
+//
+// retryablehttp performs automatic retries under certain conditions. Mainly, if
+// an error is returned by the client (connection errors etc), or if a 500-range
+// response is received, then a retry is invoked. Otherwise, the response is
+// returned and left to the caller to interpret.
+//
+// Requests which take a request body should provide a non-nil function
+// parameter. The best choice is to provide either a function satisfying
+// ReaderFunc which provides multiple io.Readers in an efficient manner, a
+// *bytes.Buffer (the underlying raw byte slice will be used) or a raw byte
+// slice. As it is a reference type, and we will wrap it as needed by readers,
+// we can efficiently re-use the request body without needing to copy it. If an
+// io.Reader (such as a *bytes.Reader) is provided, the full body will be read
+// prior to the first request, and will be efficiently re-used for any retries.
+// ReadSeeker can be used, but some users have observed occasional data races
+// between the net/http library and the Seek functionality of some
+// implementations of ReadSeeker, so should be avoided if possible.
+package retryablehttp
+
+import (
+	"bytes"
+	"context"
+	"crypto/x509"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"math"
+	"math/rand"
+	"net/http"
+	"net/url"
+	"os"
+	"regexp"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/hashicorp/go-cleanhttp"
+)
+
+var (
+	// Default retry configuration
+	defaultRetryWaitMin = 1 * time.Second
+	defaultRetryWaitMax = 30 * time.Second
+	defaultRetryMax     = 4
+
+	// defaultLogger is the logger provided with defaultClient
+	defaultLogger = log.New(os.Stderr, "", log.LstdFlags)
+
+	// defaultClient is used for performing requests without explicitly making
+	// a new client. It is purposely private to avoid modifications.
+	defaultClient = NewClient()
+
+	// We need to consume response bodies to maintain http connections, but
+	// limit the size we consume to respReadLimit.
+	respReadLimit = int64(4096)
+
+	// A regular expression to match the error returned by net/http when the
+	// configured number of redirects is exhausted. This error isn't typed
+	// specifically so we resort to matching on the error string.
+	redirectsErrorRe = regexp.MustCompile(`stopped after \d+ redirects\z`)
+
+	// A regular expression to match the error returned by net/http when the
+	// scheme specified in the URL is invalid. This error isn't typed
+	// specifically so we resort to matching on the error string.
+	schemeErrorRe = regexp.MustCompile(`unsupported protocol scheme`)
+)
+
+// ReaderFunc is the type of function that can be given natively to NewRequest
+type ReaderFunc func() (io.Reader, error)
+
+// LenReader is an interface implemented by many in-memory io.Reader's. Used
+// for automatically sending the right Content-Length header when possible.
+type LenReader interface {
+	Len() int
+}
+
+// Request wraps the metadata needed to create HTTP requests.
+type Request struct {
+	// body is a seekable reader over the request body payload. This is
+	// used to rewind the request data in between retries.
+	body ReaderFunc
+
+	// Embed an HTTP request directly. This makes a *Request act exactly
+	// like an *http.Request so that all meta methods are supported.
+	*http.Request
+}
+
+// WithContext returns wrapped Request with a shallow copy of underlying *http.Request
+// with its context changed to ctx. The provided ctx must be non-nil.
+func (r *Request) WithContext(ctx context.Context) *Request {
+	r.Request = r.Request.WithContext(ctx)
+	return r
+}
+
+// BodyBytes allows accessing the request body. It is an analogue to
+// http.Request's Body variable, but it returns a copy of the underlying data
+// rather than consuming it.
+//
+// This function is not thread-safe; do not call it at the same time as another
+// call, or at the same time this request is being used with Client.Do.
+func (r *Request) BodyBytes() ([]byte, error) {
+	if r.body == nil {
+		return nil, nil
+	}
+	body, err := r.body()
+	if err != nil {
+		return nil, err
+	}
+	buf := new(bytes.Buffer)
+	_, err = buf.ReadFrom(body)
+	if err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+// SetBody allows setting the request body.
+//
+// It is useful if a new body needs to be set without constructing a new Request.
+func (r *Request) SetBody(rawBody interface{}) error {
+	bodyReader, contentLength, err := getBodyReaderAndContentLength(rawBody)
+	if err != nil {
+		return err
+	}
+	r.body = bodyReader
+	r.ContentLength = contentLength
+	return nil
+}
+
+// WriteTo allows copying the request body into a writer.
+//
+// It writes data to w until there's no more data to write or
+// when an error occurs. The return int64 value is the number of bytes
+// written. Any error encountered during the write is also returned.
+// The signature matches io.WriterTo interface.
+func (r *Request) WriteTo(w io.Writer) (int64, error) {
+	body, err := r.body()
+	if err != nil {
+		return 0, err
+	}
+	if c, ok := body.(io.Closer); ok {
+		defer c.Close()
+	}
+	return io.Copy(w, body)
+}
+
+func getBodyReaderAndContentLength(rawBody interface{}) (ReaderFunc, int64, error) {
+	var bodyReader ReaderFunc
+	var contentLength int64
+
+	switch body := rawBody.(type) {
+	// If they gave us a function already, great! Use it.
+	case ReaderFunc:
+		bodyReader = body
+		tmp, err := body()
+		if err != nil {
+			return nil, 0, err
+		}
+		if lr, ok := tmp.(LenReader); ok {
+			contentLength = int64(lr.Len())
+		}
+		if c, ok := tmp.(io.Closer); ok {
+			c.Close()
+		}
+
+	case func() (io.Reader, error):
+		bodyReader = body
+		tmp, err := body()
+		if err != nil {
+			return nil, 0, err
+		}
+		if lr, ok := tmp.(LenReader); ok {
+			contentLength = int64(lr.Len())
+		}
+		if c, ok := tmp.(io.Closer); ok {
+			c.Close()
+		}
+
+	// If a regular byte slice, we can read it over and over via new
+	// readers
+	case []byte:
+		buf := body
+		bodyReader = func() (io.Reader, error) {
+			return bytes.NewReader(buf), nil
+		}
+		contentLength = int64(len(buf))
+
+	// If a bytes.Buffer we can read the underlying byte slice over and
+	// over
+	case *bytes.Buffer:
+		buf := body
+		bodyReader = func() (io.Reader, error) {
+			return bytes.NewReader(buf.Bytes()), nil
+		}
+		contentLength = int64(buf.Len())
+
+	// We prioritize *bytes.Reader here because we don't really want to
+	// deal with it seeking so want it to match here instead of the
+	// io.ReadSeeker case.
+	case *bytes.Reader:
+		buf, err := ioutil.ReadAll(body)
+		if err != nil {
+			return nil, 0, err
+		}
+		bodyReader = func() (io.Reader, error) {
+			return bytes.NewReader(buf), nil
+		}
+		contentLength = int64(len(buf))
+
+	// Compat case
+	case io.ReadSeeker:
+		raw := body
+		bodyReader = func() (io.Reader, error) {
+			_, err := raw.Seek(0, 0)
+			return ioutil.NopCloser(raw), err
+		}
+		if lr, ok := raw.(LenReader); ok {
+			contentLength = int64(lr.Len())
+		}
+
+	// Read all in so we can reset
+	case io.Reader:
+		buf, err := ioutil.ReadAll(body)
+		if err != nil {
+			return nil, 0, err
+		}
+		bodyReader = func() (io.Reader, error) {
+			return bytes.NewReader(buf), nil
+		}
+		contentLength = int64(len(buf))
+
+	// No body provided, nothing to do
+	case nil:
+
+	// Unrecognized type
+	default:
+		return nil, 0, fmt.Errorf("cannot handle type %T", rawBody)
+	}
+	return bodyReader, contentLength, nil
+}
+
+// FromRequest wraps an http.Request in a retryablehttp.Request
+func FromRequest(r *http.Request) (*Request, error) {
+	bodyReader, _, err := getBodyReaderAndContentLength(r.Body)
+	if err != nil {
+		return nil, err
+	}
+	// Could assert contentLength == r.ContentLength
+	return &Request{bodyReader, r}, nil
+}
+
+// NewRequest creates a new wrapped request.
+func NewRequest(method, url string, rawBody interface{}) (*Request, error) {
+	bodyReader, contentLength, err := getBodyReaderAndContentLength(rawBody)
+	if err != nil {
+		return nil, err
+	}
+
+	httpReq, err := http.NewRequest(method, url, nil)
+	if err != nil {
+		return nil, err
+	}
+	httpReq.ContentLength = contentLength
+
+	return &Request{bodyReader, httpReq}, nil
+}
+
+// Logger interface allows to use other loggers than
+// standard log.Logger.
+type Logger interface {
+	Printf(string, ...interface{})
+}
+
+// LeveledLogger interface implements the basic methods that a logger library needs
+type LeveledLogger interface {
+	Error(string, ...interface{})
+	Info(string, ...interface{})
+	Debug(string, ...interface{})
+	Warn(string, ...interface{})
+}
+
+// hookLogger adapts an LeveledLogger to Logger for use by the existing hook functions
+// without changing the API.
+type hookLogger struct {
+	LeveledLogger
+}
+
+func (h hookLogger) Printf(s string, args ...interface{}) {
+	h.Info(fmt.Sprintf(s, args...))
+}
+
+// RequestLogHook allows a function to run before each retry. The HTTP
+// request which will be made, and the retry number (0 for the initial
+// request) are available to users. The internal logger is exposed to
+// consumers.
+type RequestLogHook func(Logger, *http.Request, int)
+
+// ResponseLogHook is like RequestLogHook, but allows running a function
+// on each HTTP response. This function will be invoked at the end of
+// every HTTP request executed, regardless of whether a subsequent retry
+// needs to be performed or not. If the response body is read or closed
+// from this method, this will affect the response returned from Do().
+type ResponseLogHook func(Logger, *http.Response)
+
+// CheckRetry specifies a policy for handling retries. It is called
+// following each request with the response and error values returned by
+// the http.Client. If CheckRetry returns false, the Client stops retrying
+// and returns the response to the caller. If CheckRetry returns an error,
+// that error value is returned in lieu of the error from the request. The
+// Client will close any response body when retrying, but if the retry is
+// aborted it is up to the CheckRetry callback to properly close any
+// response body before returning.
+type CheckRetry func(ctx context.Context, resp *http.Response, err error) (bool, error)
+
+// Backoff specifies a policy for how long to wait between retries.
+// It is called after a failing request to determine the amount of time
+// that should pass before trying again.
+type Backoff func(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration
+
+// ErrorHandler is called if retries are expired, containing the last status
+// from the http library. If not specified, default behavior for the library is
+// to close the body and return an error indicating how many tries were
+// attempted. If overriding this, be sure to close the body if needed.
+type ErrorHandler func(resp *http.Response, err error, numTries int) (*http.Response, error)
+
+// Client is used to make HTTP requests. It adds additional functionality
+// like automatic retries to tolerate minor outages.
+type Client struct {
+	HTTPClient *http.Client // Internal HTTP client.
+	Logger     interface{}  // Customer logger instance. Can be either Logger or LeveledLogger
+
+	RetryWaitMin time.Duration // Minimum time to wait
+	RetryWaitMax time.Duration // Maximum time to wait
+	RetryMax     int           // Maximum number of retries
+
+	// RequestLogHook allows a user-supplied function to be called
+	// before each retry.
+	RequestLogHook RequestLogHook
+
+	// ResponseLogHook allows a user-supplied function to be called
+	// with the response from each HTTP request executed.
+	ResponseLogHook ResponseLogHook
+
+	// CheckRetry specifies the policy for handling retries, and is called
+	// after each request. The default policy is DefaultRetryPolicy.
+	CheckRetry CheckRetry
+
+	// Backoff specifies the policy for how long to wait between retries
+	Backoff Backoff
+
+	// ErrorHandler specifies the custom error handler to use, if any
+	ErrorHandler ErrorHandler
+
+	loggerInit sync.Once
+}
+
+// NewClient creates a new Client with default settings.
+func NewClient() *Client {
+	return &Client{
+		HTTPClient:   cleanhttp.DefaultPooledClient(),
+		Logger:       defaultLogger,
+		RetryWaitMin: defaultRetryWaitMin,
+		RetryWaitMax: defaultRetryWaitMax,
+		RetryMax:     defaultRetryMax,
+		CheckRetry:   DefaultRetryPolicy,
+		Backoff:      DefaultBackoff,
+	}
+}
+
+func (c *Client) logger() interface{} {
+	c.loggerInit.Do(func() {
+		if c.Logger == nil {
+			return
+		}
+
+		switch c.Logger.(type) {
+		case Logger, LeveledLogger:
+			// ok
+		default:
+			// This should happen in dev when they are setting Logger and work on code, not in prod.
+			panic(fmt.Sprintf("invalid logger type passed, must be Logger or LeveledLogger, was %T", c.Logger))
+		}
+	})
+
+	return c.Logger
+}
+
+// DefaultRetryPolicy provides a default callback for Client.CheckRetry, which
+// will retry on connection errors and server errors.
+func DefaultRetryPolicy(ctx context.Context, resp *http.Response, err error) (bool, error) {
+	// do not retry on context.Canceled or context.DeadlineExceeded
+	if ctx.Err() != nil {
+		return false, ctx.Err()
+	}
+
+	if err != nil {
+		if v, ok := err.(*url.Error); ok {
+			// Don't retry if the error was due to too many redirects.
+			if redirectsErrorRe.MatchString(v.Error()) {
+				return false, nil
+			}
+
+			// Don't retry if the error was due to an invalid protocol scheme.
+			if schemeErrorRe.MatchString(v.Error()) {
+				return false, nil
+			}
+
+			// Don't retry if the error was due to TLS cert verification failure.
+			if _, ok := v.Err.(x509.UnknownAuthorityError); ok {
+				return false, nil
+			}
+		}
+
+		// The error is likely recoverable so retry.
+		return true, nil
+	}
+
+	// Check the response code. We retry on 500-range responses to allow
+	// the server time to recover, as 500's are typically not permanent
+	// errors and may relate to outages on the server side. This will catch
+	// invalid response codes as well, like 0 and 999.
+	if resp.StatusCode == 0 || (resp.StatusCode >= 500 && resp.StatusCode != 501) {
+		return true, nil
+	}
+
+	return false, nil
+}
+
+// DefaultBackoff provides a default callback for Client.Backoff which
+// will perform exponential backoff based on the attempt number and limited
+// by the provided minimum and maximum durations.
+func DefaultBackoff(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration {
+	mult := math.Pow(2, float64(attemptNum)) * float64(min)
+	sleep := time.Duration(mult)
+	if float64(sleep) != mult || sleep > max {
+		sleep = max
+	}
+	return sleep
+}
+
+// LinearJitterBackoff provides a callback for Client.Backoff which will
+// perform linear backoff based on the attempt number and with jitter to
+// prevent a thundering herd.
+//
+// min and max here are *not* absolute values. The number to be multiplied by
+// the attempt number will be chosen at random from between them, thus they are
+// bounding the jitter.
+//
+// For instance:
+// * To get strictly linear backoff of one second increasing each retry, set
+// both to one second (1s, 2s, 3s, 4s, ...)
+// * To get a small amount of jitter centered around one second increasing each
+// retry, set to around one second, such as a min of 800ms and max of 1200ms
+// (892ms, 2102ms, 2945ms, 4312ms, ...)
+// * To get extreme jitter, set to a very wide spread, such as a min of 100ms
+// and a max of 20s (15382ms, 292ms, 51321ms, 35234ms, ...)
+func LinearJitterBackoff(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration {
+	// attemptNum always starts at zero but we want to start at 1 for multiplication
+	attemptNum++
+
+	if max <= min {
+		// Unclear what to do here, or they are the same, so return min *
+		// attemptNum
+		return min * time.Duration(attemptNum)
+	}
+
+	// Seed rand; doing this every time is fine
+	rand := rand.New(rand.NewSource(int64(time.Now().Nanosecond())))
+
+	// Pick a random number that lies somewhere between the min and max and
+	// multiply by the attemptNum. attemptNum starts at zero so we always
+	// increment here. We first get a random percentage, then apply that to the
+	// difference between min and max, and add to min.
+	jitter := rand.Float64() * float64(max-min)
+	jitterMin := int64(jitter) + int64(min)
+	return time.Duration(jitterMin * int64(attemptNum))
+}
+
+// PassthroughErrorHandler is an ErrorHandler that directly passes through the
+// values from the net/http library for the final request. The body is not
+// closed.
+func PassthroughErrorHandler(resp *http.Response, err error, _ int) (*http.Response, error) {
+	return resp, err
+}
+
+// Do wraps calling an HTTP method with retries.
+func (c *Client) Do(req *Request) (*http.Response, error) {
+	if c.HTTPClient == nil {
+		c.HTTPClient = cleanhttp.DefaultPooledClient()
+	}
+
+	logger := c.logger()
+
+	if logger != nil {
+		switch v := logger.(type) {
+		case Logger:
+			v.Printf("[DEBUG] %s %s", req.Method, req.URL)
+		case LeveledLogger:
+			v.Debug("performing request", "method", req.Method, "url", req.URL)
+		}
+	}
+
+	var resp *http.Response
+	var err error
+
+	for i := 0; ; i++ {
+		var code int // HTTP response code
+
+		// Always rewind the request body when non-nil.
+		if req.body != nil {
+			body, err := req.body()
+			if err != nil {
+				c.HTTPClient.CloseIdleConnections()
+				return resp, err
+			}
+			if c, ok := body.(io.ReadCloser); ok {
+				req.Body = c
+			} else {
+				req.Body = ioutil.NopCloser(body)
+			}
+		}
+
+		if c.RequestLogHook != nil {
+			switch v := logger.(type) {
+			case Logger:
+				c.RequestLogHook(v, req.Request, i)
+			case LeveledLogger:
+				c.RequestLogHook(hookLogger{v}, req.Request, i)
+			default:
+				c.RequestLogHook(nil, req.Request, i)
+			}
+		}
+
+		// Attempt the request
+		resp, err = c.HTTPClient.Do(req.Request)
+		if resp != nil {
+			code = resp.StatusCode
+		}
+
+		// Check if we should continue with retries.
+		checkOK, checkErr := c.CheckRetry(req.Context(), resp, err)
+
+		if err != nil {
+			switch v := logger.(type) {
+			case Logger:
+				v.Printf("[ERR] %s %s request failed: %v", req.Method, req.URL, err)
+			case LeveledLogger:
+				v.Error("request failed", "error", err, "method", req.Method, "url", req.URL)
+			}
+		} else {
+			// Call this here to maintain the behavior of logging all requests,
+			// even if CheckRetry signals to stop.
+			if c.ResponseLogHook != nil {
+				// Call the response logger function if provided.
+				switch v := logger.(type) {
+				case Logger:
+					c.ResponseLogHook(v, resp)
+				case LeveledLogger:
+					c.ResponseLogHook(hookLogger{v}, resp)
+				default:
+					c.ResponseLogHook(nil, resp)
+				}
+			}
+		}
+
+		// Now decide if we should continue.
+		if !checkOK {
+			if checkErr != nil {
+				err = checkErr
+			}
+			c.HTTPClient.CloseIdleConnections()
+			return resp, err
+		}
+
+		// We do this before drainBody because there's no need for the I/O if
+		// we're breaking out
+		remain := c.RetryMax - i
+		if remain <= 0 {
+			break
+		}
+
+		// We're going to retry, consume any response to reuse the connection.
+		if err == nil && resp != nil {
+			c.drainBody(resp.Body)
+		}
+
+		wait := c.Backoff(c.RetryWaitMin, c.RetryWaitMax, i, resp)
+		desc := fmt.Sprintf("%s %s", req.Method, req.URL)
+		if code > 0 {
+			desc = fmt.Sprintf("%s (status: %d)", desc, code)
+		}
+		if logger != nil {
+			switch v := logger.(type) {
+			case Logger:
+				v.Printf("[DEBUG] %s: retrying in %s (%d left)", desc, wait, remain)
+			case LeveledLogger:
+				v.Debug("retrying request", "request", desc, "timeout", wait, "remaining", remain)
+			}
+		}
+		select {
+		case <-req.Context().Done():
+			c.HTTPClient.CloseIdleConnections()
+			return nil, req.Context().Err()
+		case <-time.After(wait):
+		}
+	}
+
+	if c.ErrorHandler != nil {
+		c.HTTPClient.CloseIdleConnections()
+		return c.ErrorHandler(resp, err, c.RetryMax+1)
+	}
+
+	// By default, we close the response body and return an error without
+	// returning the response
+	if resp != nil {
+		resp.Body.Close()
+	}
+	c.HTTPClient.CloseIdleConnections()
+	return nil, fmt.Errorf("%s %s giving up after %d attempts",
+		req.Method, req.URL, c.RetryMax+1)
+}
+
+// Try to read the response body so we can reuse this connection.
+func (c *Client) drainBody(body io.ReadCloser) {
+	defer body.Close()
+	_, err := io.Copy(ioutil.Discard, io.LimitReader(body, respReadLimit))
+	if err != nil {
+		if c.logger() != nil {
+			switch v := c.logger().(type) {
+			case Logger:
+				v.Printf("[ERR] error reading response body: %v", err)
+			case LeveledLogger:
+				v.Error("error reading response body", "error", err)
+			}
+		}
+	}
+}
+
+// Get is a shortcut for doing a GET request without making a new client.
+func Get(url string) (*http.Response, error) {
+	return defaultClient.Get(url)
+}
+
+// Get is a convenience helper for doing simple GET requests.
+func (c *Client) Get(url string) (*http.Response, error) {
+	req, err := NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	return c.Do(req)
+}
+
+// Head is a shortcut for doing a HEAD request without making a new client.
+func Head(url string) (*http.Response, error) {
+	return defaultClient.Head(url)
+}
+
+// Head is a convenience method for doing simple HEAD requests.
+func (c *Client) Head(url string) (*http.Response, error) {
+	req, err := NewRequest("HEAD", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	return c.Do(req)
+}
+
+// Post is a shortcut for doing a POST request without making a new client.
+func Post(url, bodyType string, body interface{}) (*http.Response, error) {
+	return defaultClient.Post(url, bodyType, body)
+}
+
+// Post is a convenience method for doing simple POST requests.
+func (c *Client) Post(url, bodyType string, body interface{}) (*http.Response, error) {
+	req, err := NewRequest("POST", url, body)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", bodyType)
+	return c.Do(req)
+}
+
+// PostForm is a shortcut to perform a POST with form data without creating
+// a new client.
+func PostForm(url string, data url.Values) (*http.Response, error) {
+	return defaultClient.PostForm(url, data)
+}
+
+// PostForm is a convenience method for doing simple POST operations using
+// pre-filled url.Values form data.
+func (c *Client) PostForm(url string, data url.Values) (*http.Response, error) {
+	return c.Post(url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
+}
+
+// StandardClient returns a stdlib *http.Client with a custom Transport, which
+// shims in a *retryablehttp.Client for added retries.
+func (c *Client) StandardClient() *http.Client {
+	return &http.Client{
+		Transport: &RoundTripper{Client: c},
+	}
+}
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/go.mod b/vendor/github.com/hashicorp/go-retryablehttp/go.mod
new file mode 100644
index 0000000000..7cc02b76fa
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-retryablehttp/go.mod
@@ -0,0 +1,8 @@
+module github.com/hashicorp/go-retryablehttp
+
+require (
+	github.com/hashicorp/go-cleanhttp v0.5.1
+	github.com/hashicorp/go-hclog v0.9.2
+)
+
+go 1.13
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/go.sum b/vendor/github.com/hashicorp/go-retryablehttp/go.sum
new file mode 100644
index 0000000000..71afe56822
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-retryablehttp/go.sum
@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/hashicorp/go-cleanhttp v0.5.1 h1:dH3aiDG9Jvb5r5+bYHsikaOUIpcM0xvgMXVoDkXMzJM=
+github.com/hashicorp/go-cleanhttp v0.5.1/go.mod h1:JpRdi6/HCYpAwUzNwuwqhbovhLtngrth3wmdIIUrZ80=
+github.com/hashicorp/go-hclog v0.9.2 h1:CG6TE5H9/JXsFWJCfoIVpKFIkFe6ysEuHirp4DxCsHI=
+github.com/hashicorp/go-hclog v0.9.2/go.mod h1:5CU+agLiy3J7N7QjHK5d05KxGsuXiQLrjA0H7acj2lQ=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/roundtripper.go b/vendor/github.com/hashicorp/go-retryablehttp/roundtripper.go
new file mode 100644
index 0000000000..b841b4cfe5
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-retryablehttp/roundtripper.go
@@ -0,0 +1,43 @@
+package retryablehttp
+
+import (
+	"net/http"
+	"sync"
+)
+
+// RoundTripper implements the http.RoundTripper interface, using a retrying
+// HTTP client to execute requests.
+//
+// It is important to note that retryablehttp doesn't always act exactly as a
+// RoundTripper should. This is highly dependent on the retryable client's
+// configuration.
+type RoundTripper struct {
+	// The client to use during requests. If nil, the default retryablehttp
+	// client and settings will be used.
+	Client *Client
+
+	// once ensures that the logic to initialize the default client runs at
+	// most once, in a single thread.
+	once sync.Once
+}
+
+// init initializes the underlying retryable client.
+func (rt *RoundTripper) init() {
+	if rt.Client == nil {
+		rt.Client = NewClient()
+	}
+}
+
+// RoundTrip satisfies the http.RoundTripper interface.
+func (rt *RoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	rt.once.Do(rt.init)
+
+	// Convert the request to be retryable.
+	retryableReq, err := FromRequest(req)
+	if err != nil {
+		return nil, err
+	}
+
+	// Execute the request.
+	return rt.Client.Do(retryableReq)
+}